Wha. Dokter et al., INTERLEUKIN-4 MESSENGER-RNA AND PROTEIN IN ACTIVATED HUMAN T-CELLS ARE ENHANCED BY INTERLEUKIN-7, Experimental hematology, 22(1), 1994, pp. 74-79
We studied the effect of the stroma-derived cytokine interleukin-7 (IL
-7) on the expression of IL-4 in human T cells at mRNA and protein lev
el. The results demonstrate that IL-7 did not induce IL-4 mRNA in rest
ing T cells. However, concanavalin A (con A)-induced IL-4 mRNA. expres
sion was enhanced by costimulation with con A plus IL-7. Nuclear run-o
n analysis revealed that IL-7 did not affect the transcription rate of
the IL-4 gene. The half-life of con A-induced IL-4 transcripts, howev
er, was increased upon con A plus IL-7 treatment, indicating that the
effect of IL-7 is mediated at posttranscriptional level. In accordance
with the mRNA results, IL-4 protein was not detected in supernatants
of unstimulated T cells or T cells exposed to IL-7. In contrast, IL-7
augmented the con A-induced secretion of IL-4 protein significantly. I
n addition, it was noticed that anti-IL-1 beta and anti-tumor necrosis
factor-a (anti-TNF-alpha) did not abolish the effect of IL-7 on the c
on A-induced IL-4 secretion, indicating that the IL-7 effect is not me
diated by the release of these cytokines. These results indicate that
a stroma-derived factor can affect IL-4 expression in activated human
T cells.